Determining the Removal, Recovery, and Recycles of Au(III) from Aqueous Au(III) Solution Using Immobilized Pseudomonas Cells by Biomineralization and Thiourea Oxidation

Recently, some researchers have investigated the recovery of gold using microbial cells, such as bacteria, fungi, yeasts, and algae. However, there is little information on which kind of microorganisms has a high gold adsorbing ability. We have reported various species and strains of bacteria, actinomycetes, fungi, and yeasts were screened for their ability to adsorb gold from a solution containing hydrogen tetrachloroaurate (III). Hydrogen tetrachloroaurate (III) is used for medical and ceramic materials. The effect of pH, external gold concentration, cell amounts on gold biosorption, and the time course of gold biosorption by Pseudomonas maltophilia cells, which adsorbed large amounts of gold from a solution containing hydrogen tetrachloroaurate (III), were reported in detail. In this chapter, in order to approve the amount of gold recovery much higher, the removal of gold (III) by biosorption and biomineralization from aqueous systems using microbial cells, gold (III) removal by those using microbial cells was investigated. Additionally, the oxidative recovery of gold after reduced gold(0) by the oxidation using aqueous thiourea solution, and recycles of gold reduction-oxidation cycles.